1. Field of the Invention
The present invention relates to an intraductal insertion device which can advance and retract an insertion portion in a duct using thrust developed by a thrust generating section.
2. Description of the Related Art
Conventionally, an intraductal insertion device such as a catheter is inserted directly into the urethra or the like. Also, an elongated insertion portion of an endoscope is inserted, for example, into the stomach through the oral cavity, or into the large intestine or the like through the anus.
Generally, the endoscope is equipped with a bending portion on a distal end side of the elongated insertion portion, where the bending portion is configured by linking bending pieces together, for example, to perform bending operation in up-and-down and left-to-right directions. The bending portion is configured to perform bending operation when a surgeon operates, for example, a bending knob provided in an operation section and thereby advances and retracts an operation wire connected to the bending pieces.
It requires skill to learn to pass the insertion portion of the endoscope smoothly through an intricate duct in a short time. In particular, surgeons inexperienced in handling endoscopes used to take a lot of time inserting the insertion portion into deep part of the large intestine. Thus, in order to improve insertability of the insertion portion, various proposals have been made to pass the insertion portion through to a target site by means of thrust.
For example, U.S. Pat. No. 7,048,717 discloses an endoscope insertion aid device and the like equipped with a spiral structure. With the endoscope insertion aid device, when a spiral structural portion provided in an insertion portion of an endoscope is rotated around the axis of the insertion portion by rotating a handle, the spiral structural portion and large intestine walls form a relationship such as between an external thread and an internal thread, providing thrust for the insertion portion to move forward in the intestine.
On the other hand, Japanese Patent Application Laid-Open Publication No. 2006-523513 (hereinafter referred to as Patent Document 2) discloses a self-propelled endoscope apparatus used to transport ancillary devices to a desired location in a tubular space and environment in which medical and non-medical procedures are carried out. The self-propelled endoscope apparatus is made up of a flexible toroid filled with a fluid, and a frame equipped with a power unit or a frame supplied with power. A surface of the toroid of the endoscope apparatus circulates around the toroid by a continuous motion along a central axial line of the toroid, moving from inside a central cavity of the toroid to outside the toroid where the surface rotates in an opposite direction and returning again to the central cavity. The toroid is designed such that direction and speed of the toroid motion is controllable. Consequently, for example, when a colonoscope is inserted in a tubular space or environment such as the colon of a patient, the circulated toroid surface comes into contact with an inner surface of the tubular space, causing the endoscope apparatus to advance or retract.